COMPARISON OF CELL RESPONSE ON COLLAGEN FIBRIL THIN FILMS
CREATED FROM DIFFERENT SOURCES OF TYPE 1 COLLAGEN

Tighe A. Spurlin, John Elliott, and Anne L.
Plant

The majority of cell-based
assays performed to elucidate cellular pathways and responses to drugs and
toxins have been performed in cells on plasma treated polystyrene dishes or
ill-defined extracellular matrix (ECM) protein coatings. In many studies, cell
responses have been shown to be sensitive to surface topography, protein
coverage, surface chemistry, and extracellular matrix composition,
supramolecular structure, and mechanical features. Type I collagen gels have
been widely used as model ECM systems for cell studies, since collagen is a
highly prevalent ECM in vivo. However, gels are fragile structures that
are difficult to characterize and use with quantitative optical microscopy. We
have previously shown that thin films of Type I collagen fibrils can be used to
alleviate the difficulties associated with collagen gels. Thin films of collagen
fibrils have been shown to provide cells with an ECM environment that induces
cell responses that are indistinguishable from those seen in cells on the thicker
gels in terms of spreading, proliferation, integrin ligation, and tenascin-C
expression. Thin films of collagen are highly reproducible, but we have up to
now only used one source of Type I collagen to prepare them. To determine if
different sources of Type I collagen can be used to create a robust,
reproducible, and standardized biomimetic surface for cell assay applications,
we prepared films using type I collagen from different manufactures and
characterized them with atomic force microscopy and optical microscopy. Results
from this series of studies illustrate that collagen films created using the
same protocol but different comparable sources of collagen show fibril content
that ranges from 43.4 % ± 1.32 % to 6.6 % ± 0.6 %. In initial studies we have
observed that vascular smooth muscle cell spread area can differ dramatically
from 2043 µm2 ± 121 µm2 to 6616 µm2 ± 237 µm2
depending on the source of the Type I collagen used. The findings suggest that
different Type 1 collagen preparations are not identical, and highlight the
importance of carefully characterizing and reporting the characteristics of the
surfaces that cells are grown on during biological assays.